Project Summary Infancy is a critical window for language development and an undiagnosed hearing impairment during this time can lead to lifelong speech and language deficits. Identification and treatment of a hearing impairment before 6mo can lead to language outcomes nearly equivalent to normal hearing peers12-14. The benefit of intervention before 6mo has led to the 1-3-6 guidelines, where all infants should be screened for hearing impairment by 1 month, diagnosed by 3 months, and prescribed intervention by 6 months. However, it can be difficult to obtain an accurate diagnosis of hearing impairment by this age as behavioral assessments can be subjective and unreliable until after 6mos20. Physiological measures such as Otoacoustic Emmissions (OAE) or Auditory Brainstem Response (ABR) provide objective measures of hearing from birth, however may not produce a completely accurate audiogram as they only assess functioning in portions of the auditory system18,19. Only behavioral testing can provide a direct measure of hearing19, but current technologies leave the audiology community without an objective behavioral assessment of hearing within the 1-3-6 timeline. This proposal investigates the technical merit of using sucking activity as an objective behavioral assessment of hearing in infants before 6mos. Sucking is an innate behavior that infants can control from birth. It can be objectively measured and infants are already known to alter their sucking in response to sounds19,24. The proposal will leverage Brainchild Technologies previously developed Smart Pacifier that can objectively measure changes in an infant's sucking behavior in response to images and sounds. Specific Aim I will create Smart Pacifier-connected software that can serve as a digital audiometer and measures infants' sucking behavior in response to the presentation of tones normally used in behavioral audiometry. Specific Aim 2 will conduct a proof-of-concept study to assess if this Smart Pacifier platform will engage normal hearing infants younger than 6mo long enough to produce an audiogram. The proof-of-concept in infants will focus on 3 behavioral paradigms: passive-sucking, contingent sucking, and operant conditioned sucking.